Locusts
are regularly in the news.
After a 20 year
lull, Desert Locusts infested 22
countries from 2003-2005,
and 13 million L of mainly organophosphate pesticides were applied
over roughly the same surface in hectares.

The
normal method of controlling these pests is
with chemical pesticides, using ultra-low
volume (ULV) application methods. When protecting crops
a quick “knock-down” is required and fast acting insecticides,
such as pyrethroids, are required. However, many of these
chemicals cause environmental damage and some are hazardous to
humans and domestic animals. The FAO
Pesticides Referee Group (PRG) advises on application rates
of insecticides used in locust control and on the potential environmental
risk of these products. FAO
also provide technical
bulletins on locust control.

In
response to concerns
over pesticide use, an internationally funded and executed
Programme called LUBILOSA[1] was set-up for biological control
of locusts and grasshoppers in environmentally sensitive areas.
The Programme very rapidly focused on the development of a fungus
called Metarhiziumacridum
as the most promising agent for biological control.

The
potential for using Metarhiziumas a pest control agent was first observed over a century ago by
the Russian scientist Ilya Ilich Metschnikoff. Since then much
has been written about the use of this fungus, together with other species
such as Beauveria bassiana, as insect control agents (mycoinsecticides),
but unfortunately chemicals remain prevalent. One of the key constraints
was that Metarhizium and Beauveria, like other fungi,
usually require high humidity in order to infect their hosts.
A critical discovery changed this. Dr Chris Prior observed that
spores of these fungi could be more infectious when formulated in oil[2], with their action more independent
of environmental conditions.

spores of Metarhizium acridum in an
oil formulation germinating on locust cuticle

the parasitic was Pryonyx, another
natural enemy a tree locust (which is not affected by the locust
isolate of Metarhizium)

This
discovery led to the development of an oil-based fungal product that
could be applied in a very similar way to standard locust control chemicals,
which are also formulated in oil. I called this product 'Green
Muscle'™ (a play on the
English name for Metarhizium: the 'green muscardine fungus')
and it seems to have caught on. The genus Metarhizium can
be used to kill a wide range of insects, but 'Green Muscle' is based
on a specific isolate which targets locusts and grasshoppers, and has
been proved to work effectively. However 'Green Muscle is specific,
and only works against species within this group[3] Specificity is an important
feature of biological pesticides, because they have little or no adverse
environmental impact, benefiting not only humans but also other animals:
including the natural enemies of the pests themselves. However,
from a commercial point of view, this severely limits markets and biopesticides
are most likely to be produced by the small-medium sized enterprises.
Therefore ready-made solutions are required for any problems in technical
development.

During
the course of the Programme, it became clear that two of the key technical
challenges in the development of mycoinsecticide product were mass production
and delivery systems (including formulation
and application).
These procedures are linked by a critical process: the separation of
fungus spores from their substrate, and a purpose-built device developed
which eventually "evolved" into a device called the ‘MycoHarvester’.
This is an example of an "enabling technology", which can
assist in the exploitation of a range of micro-organisms environmentally
safe pest control for both Western and developing countries.

Green
Muscle has now been adopted by commercial
partners and successful operations continue to be reported - including
a recent example - control
of the red locust in East Africa. However, reaching this stage was
expensive: the LUBILOSA Programme eventually cost donors approximately
€15 million (although this is an order of magnitude cheaper than developing
a chemical pesticide). Perhaps equally important are the "spin
offs" that enable research groups around the World to bring about
biological control solutions for other pests more rapidly, using similar
technologies.

[1]LUtte BIologique contre les LOcustes et les SAuteriaux: a collaborative, multi-disciplinary research and
development programme funded by the Governments of Canada (CIDA),
the Netherlands (DGIS), Switzerland (SDC) and the UK (DfID).